Statistical Power in Stuttering Research A Tutorial Tutorial
Tutorial  |   April 01, 2002
Statistical Power in Stuttering Research
 
Author Affiliations & Notes
  • Mark Jones
    National Health and Medical Research Council of Australia Clinical Trials Centre The University of Sydney Australia
  • Val Gebski
    National Health and Medical Research Council of Australia Clinical Trials Centre The University of Sydney Australia
  • Mark Onslow, PhD
    Australian Stuttering Research Centre The University of Sydney Australia
  • Ann Packman
    Australian Stuttering Research Centre The University of Sydney Australia
  • Contact author: Mark Onslow, PhD, Australian Stuttering Research Centre, The University of Sydney, P.O. Box 170, Lidcombe NSW 1825, Australia. E-mail: M.Onslow@fhs.usyd.edu.au
Article Information
Speech, Voice & Prosodic Disorders / Fluency Disorders / Research Issues, Methods & Evidence-Based Practice / Speech / Tutorial
Tutorial   |   April 01, 2002
Statistical Power in Stuttering Research
Journal of Speech, Language, and Hearing Research, April 2002, Vol. 45, 243-255. doi:10.1044/1092-4388(2002/019)
History: Received July 31, 2001 , Accepted November 21, 2001
 
Journal of Speech, Language, and Hearing Research, April 2002, Vol. 45, 243-255. doi:10.1044/1092-4388(2002/019)
History: Received July 31, 2001; Accepted November 21, 2001
Web of Science® Times Cited: 18

The capacity to make reliable inductive statements about populations is critical for the advancement of scientific knowledge. An important contribution to that advancement of knowledge is determining that effects are either present or not present in populations. Statistical power is an important methodological qualifica-tion for any research that presents statistical results, and particularly so for research that presents null results. In this paper we describe the statistical concept of power, outline parameters of research that influence it, and demonstrate how it is calculated. With reference to selected published research, attention is drawn to the problems associated with a body of underpowered research, one being that population effects may go undetected. One way to prevent this problem is to calculate power a priori in planning research and include confidence intervals when presenting the results of research. However, it is difficult, if not impossible in many cases, to obtain high participant numbers for communication disorders of low prevalence such as stuttering. With this in mind, the paper concludes with an attempt to open discussion about ways to redress the problems associated with statistical power.

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